R.O.B.O.T Relatively Obedient Being Of T

Control the last KX-3700 Army-class robot in existence against the never ending onslaught of other robots sent to terminate you. Upgrade yourself in 8 different tracks. Version 5 will get you the tier 2 upgrade and version 9 will get you tier 3. How long can you survive?

Controls:
Fire: left_mouse
Movement: wasd

Instructions:
You must destroy the incoming robots and try to survive for as long as you can. Between each round there is a chance to upgrade your robot after you gain cores.